.\"	$OpenBSD: SSL_get_peer_cert_chain.3,v 1.5 2018/03/27 17:35:50 schwarze Exp $
.\"	OpenSSL SSL_get_peer_cert_chain.pod 1f164c6f Jan 18 01:40:36 2017 +0100
.\"	OpenSSL SSL_get_peer_cert_chain.pod 9b86974e Aug 17 15:21:33 2015 -0400
.\"
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.Dd $Mdocdate: March 27 2018 $
.Dt SSL_GET_PEER_CERT_CHAIN 3
.Os
.Sh NAME
.Nm SSL_get_peer_cert_chain
.Nd get the X509 certificate chain sent by the peer
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft STACK_OF(X509) *
.Fn SSL_get_peer_cert_chain "const SSL *ssl"
.Sh DESCRIPTION
.Fn SSL_get_peer_cert_chain
returns a pointer to
.Dv STACK_OF Ns Po Vt X509 Pc
certificates forming the certificate chain of the peer.
If called on the client side, the stack also contains the peer's certificate;
if called on the server side, the peer's certificate must be obtained
separately using
.Xr SSL_get_peer_certificate 3 .
If the peer did not present a certificate,
.Dv NULL
is returned.
.Pp
.Fn SSL_get_peer_cert_chain
returns the peer chain as sent by the peer: it only consists of
certificates the peer has sent (in the order the peer has sent them)
and it is not a verified chain.
.Pp
If the session is resumed, peers do not send certificates, so a
.Dv NULL
pointer is returned.
Applications can call
.Fn SSL_session_reused
to determine whether a session is resumed.
.Pp
The reference count of the
.Dv STACK_OF Ns Po Vt X509 Pc
object is not incremented.
If the corresponding session is freed, the pointer must not be used any longer.
.Sh RETURN VALUES
The following return values can occur:
.Bl -tag -width Ds
.It Dv NULL
No certificate was presented by the peer or no connection was established or
the certificate chain is no longer available when a session is reused.
.It Pointer to a Dv STACK_OF Ns Po X509 Pc
The return value points to the certificate chain presented by the peer.
.El
.Sh SEE ALSO
.Xr ssl 3 ,
.Xr SSL_get_peer_certificate 3
.Sh HISTORY
.Fn SSL_get_peer_cert_chain
first appeared in SSLeay 0.8.0 and has been available since
.Ox 2.4 .
